Are Scientists Overselling Climate Models?

According to a 2007 report by the U.N. Intergovernmental Panel on Climate Change (IPCC), a group of hundreds of scientists that assesses and reports on climate change research, state-of-the-art climate models indicate the odds are about 90% that manmade influences are and will continue to be the principal cause of global warming. Model estimates of global average temperature rise over the 21st century range from 3.2°F to 7.2°F.

To what extent should we accept these projections at face value? How certain is the stated range of uncertainty? Can today's climate models provide credible predictions of the regional impacts of climate change (e.g., on the scale of U.S. states or most European countries)?

These questions are addressed in a series of recent articles and exchange of comments in New Scientist.

Keep reading for more on the certainty (or lack there of) of climate models...

Lenny Smith, a statistics professor at the London School of Economics and Political Science (and someone who I've worked with in the past and regard highly), believes human activities are changing the global climate, but that climate scientists are "overselling" their results.

"...we must stop pretending that we know the details of how it will all play out," comments Lenny, who points out that the estimates of uncertainty -- based on the distribution of results from as many as 300 runs of global climate models -- are themselves uncertain. This is especially true, he says, in the extremes (or "tails") of the distribution, which are often particularly important for decision-makers. Thus, it's quite possible that future warming could be significantly more or less than the range indicated by the models.

Moreover, as I indicated in an earlier post, the credibility of climate models is especially questionable with regard to forecasting regional aspects of climate change.

In questions and comments responding to Lenny's remarks, the obvious issue raised is whether we should believe the reports of the IPCC and, by inference, any statements by climate scientists based on climate models. Lenny and others say broadly yes -- as long as the qualifiers are acknowledged and carefully read. To that end, they point to one item in particular -- buried deep in the report's first section (chapter 10) -- that has likewise bothered me. Namely, the report explicitly acknowledges that the range of uncertainty in warming is too narrow. But, to quote one commenter, "It's good that the qualifier is in there, but it is a hell of a qualifier to find on page 797."

So while climate models should not be ignored, the majority of climate scientists who believe that humans are contributing to global warming should be especially forthright in not overselling their case. To which I must add that global warming skeptics should be equally concerned about not overstating their position by exaggerating justifiable questions about the credibility of climate models.

An egregious example of such exaggeration is one contributor to the New Scientist articles who argues it's about time that "climate modelers may have to recognize that we have learned most of what we can from their number crunching." In truth, as data increases, research builds and technology advances, climate models are undoubtedly providing ever increasing knowledge and understanding of the fundamental processes that govern Earth's climate system.

Overall, there is agreement that climate models can be valuable decision-making tools. They can yield information on plausible risks and minimize vulnerability, although not necessarily provide totally reliable estimates of the odds. As Lenny puts it: "When I cross the street, average statistics about cars and how they are driven are of less value to me than the sound of a bus heading my way. Models help us listen for that bus." In other words, models can tell us what to listen for, such as increasing levels of atmospheric carbon dioxide.

To me, the most important question is how societies respond to the reasonable, albeit less-than-certain chance that human-caused global warming and its consequences will continue -- and that it might possibly reach extremes not now encompassed by climate models. This is a classic example of risk analysis and decision making -- i.e., weighing the costs of action to reduce carbon dioxide emissions, which conceivably might not be the cause of global warming or may cause less warming than predicted, versus the costs of inaction, which could have profound negative societal impacts if, as is more likely, carbon dioxide is a principal driver of global warming.

Whatever the case, careless use of results obtained from climate models, as well as unwarranted skepticism of climate scientists and their models, can unnecessarily muddy the waters and lead to delays in critically urgent policy decisions.

""...we must stop pretending that we know the details of how it will all play out,"

Hmmm... who do we know on this web site that has been saying that all along???

Oh yea. That would be me.

But I can't take too much credit. It was obvious to anyone who was not an ideologue.

Are you paying attention Mr. Freedman? This whole thing has been grossly oversold. And this is how it will all unwind - gradually. Gradually scientists will switch sides, as they already are. Gradually expectations will be lowered. Gradually it will become a non-issue; a non-story. But, with the memory of the Internet being complete and eternal, you will be left holding the bag so to speak, with all of your columns.

As usual, we have yet another column where someone tries to convince the public that SOMETHING must be done, and they don't say what must be done. I find it particularly amusing when Mr. Freedman does it. One would expect someone who is pursuing a masters degree in "climate change policy" to be able to at least suggest one, just one, policy. Alas, no such luck.

Perhaps you, Dr. Tracton, will put forward a suggestion on what you think should be done to mitigate any potential risk?

I will. I propose that begin an immediate, but slow and gradual, replacement of existing coal fired power plants with nuclear power plants.

Please keep in mind that these climate models are somewhat untested. We are talking about long-term computer models and not the familiar "weather" models such as the NAM, GFS, RUC, and ECMWF. These short-term models are relatively well-tested and do spit out predictions based on the incoming input. Even so, the "weather" models frequently disagree and are only as good as the accuracy of input data. As folks say in the IT community "GIGO"--"garbage in, garbage out". The same will hold just as true, if not more so, of the long-term climate models.

Please remember that a human brain is still needed to summarize and interpret the often-"dueling" computer-generated output.

You are overselling it Dr. Tracton. By the way, I am still waiting for your suggestions on how to mitigate any potential global warming risk.

I will be impressed with a survey when the scientists put their name down in support of an unequivocal statement. When they record their name, in public, to that unequivocal statement in support of catastrophic man made global warming, please let me know.

The people on Senator Inhofe's list are not anonymous. They are prominent scientists putting their name down on the public record with unequivocal statements against the current propaganda of catastrophic man made global warming.

There is a bottom line to this. As the polar ice caps melt (yes they are! Its not hard to measure.), sea levels will rise - like filling up a bath tub. As sea levels rise, lower lying coast lines will be innundated (And wealthy individuals with sea-side homes will be pleading for Federal assistance - think Trent Lott's sea-side villa on the Gulf coast). As I tell my students; global warming is not a theory, its a measurement. The BASIS for the increase in temperature has many theories. But the warming trend will melt ploar ice caps, and produce migration of animals and insects, and alter which crops can be planted at a particular latitude. These are (as we say in the Army) "facts on the ground."

"As the polar ice caps melt (yes they are! Its not hard to measure.), sea levels will rise - like filling up a bath tub."

In the Antarctic, if the ice melts off the land, yes. But I think if you check, the Arctic ice is free-floating. If you melt an ice cube in a glass of water, the level of the water does not change.... The mass of the floating ice and the mass of the water it displaces is equal.

The latest Smithsonian "Air and Space" magazine has an article about cameras and observations of Mars, and points out that the polar caps on Mars are disappearing, which I keep thinking about when the human effects question comes up.

A fairly recent issue of Nature contained a book review of "Global Catastrophic Risks" which heavily criticized the book for "downplaying" the risks of global warming. Such terminology is already full of irrational bias--the authors of the book that was reviewed more accurately did not hyperbollically overstate the risks of global warming, and were criticized for not being sufficiently panicked. Instead, they had the gumption to focus on understood, tangible risks that could result in the instantaneous destruction of life on earth TODAY (e.g. nuclear holcaust, pandemics natural and man-made, asteroid strikes).

What should be clear to everyone is that global warming is not going to end life on earth. In fact, life prospered quite nicely in the past at warmer temperatures. The RATE of warming is, however, troublesome, simply because species, including us, cannot adapt that quickly. While a major nuisance, it is still one whose effects will take place over many, many decades, and I personally have trouble viewing some predicted outcomes, such as the slow inundation of most coastal cities as being a net negative for the planet. I believe an earnest, informed, and methodical approach is needed rather than the mass-hysteria that is occurring now and leading to unintended HIGHLY NEGATIVE consequences, such as the poor uneducated masses embracing technology that contain the seeds of even more disastrous environmental catastrophes (e.g. BATTERIES).

People tend to feel good about how the miniscule reductions in carbon footprints might one day slow the glacial pace of the global warming "catastrophe", but I can only hope that they will not be lulled into ignoring the real imminent threats from natural and man-made disasters that can cause instaneous devstation. But that would be to assume that humans are much less foolish than history has shown them to be.

In a nutshell, give me scientists and leaders who can intelligently and honestly prioritize risk.

The key point to me is this: If we err on the side of pessimism, we risk spending several billions that we could have saved, on emission reduction and carbon capture programs.

If we err on the side of optimism, we risk signing our death warrant as a species.

Imagine how we will feel if the predictions cristallise into a reality that, yes, man-made emissions are causing a greenhouse effect, but it's now too late to stop it. Imagine how our kids and grandchildren will look at us.

On Friday, January 16, the U.S. Climate Change Science Program released four new reports. They are:

Final Report of Synthesis and Assessment Product 4.1 Coastal Sensitivity to Sea-Level Rise: A Focus on the Mid-Atlantic Region is posted online. See also press release from the Environmental Protection Agency (EPA), and EPA web-page.

Final Report of Synthesis and Assessment Product 4.2 Thresholds of Climate Change in Ecosystems is posted. See also press release from the U.S. Geological Survey (USGS).

Final Report of Synthesis and Assessment Product 2.3 Aerosol properties and their impacts on climate is posted online. See also press release from the National Aeronautics and Space Administration (NASA).

Final Report of Synthesis and Assessment Product 1.2 Past Climate Variability and Change in the Arctic and at High Latitudes is posted. See also press release from the U.S. Geological Survey (USGS).

These are substantive and comprehensive studies that should be read by everyone posting comments on this thread.

capybara, I watched your youtube video. I found it to be the perfect companion to this column. It was a video representation of the overselling of the science and the doom and gloom. I couldn't have picked a better video to illustrate the overselling if I had tried. Thank you.

What policies or actions do you propose to help mitigate any potential risk? Please be specific.

Dr. Tracton, how is that list of recommended policies/actions to mitigate any potential global warming risk coming? Perhaps Mr. Freedman can give you a hand with it.

It's a very sensible column. But perhaps the most important line in it is this one:

"To which I must add that global warming skeptics should be equally concerned about not overstating their position by exaggerating justifiable questions about the credibility of climate models."

The climate change skeptics are so desperate, and so discredited these days that they are like starving tigers. If a zookeeper walks into their lair holding a piece of raw meat to feed them, they will leap at the keeper and devour not only the morsel he is holding, but the keeper with it.

Thus I wince whenever a new paper comes out indicating (qualitatively and colloquially put) that instead of an impending disaster on our hands, what we *might* have is just a really, really damaging and painful situation. The skeptics take that and run with it all the way to Marathon when it was really a message meant to be delivered down the block. They make me downright dizzy with their desperate reactions to the normal scientific back-and-forth process.

Firstly, the climate has always been changing and will continue to change long after we're gone--look at the ice core data...you should be more concerned with global cooling and the impending starvation than Dick Cheney's house getting flooded. Secondly, CO2 is not a pollutant, so stop selling that to the public. Thirdly, even assuming the models are correct, the green house effect should be a forced system unitl it reaches some equilibrium point (i.e. hotter earth causes more CO2 to be released in a viscous cycle). Just because a loud noise can start an avalanche doesn't mean you can stop one by yelling at the mountain.
If you need a cause or something tho "worry" about in order to feel part of the human race, how about nuclear proliferation, religious extremism, AIDS, poverty, adult illiteracy, women's rights and cancer--all of which are well understood problems with possible solutions.

NOAA NCDC says the trend is +.12 degF per decade so in 100 years, were that trend to continue, it will be 53.06 + 1.2 = 54.26 degF which will be COOLER than 2006, 1998, or 1934

Further:
Antarctic has about 10% MORE or 1.1 million more square miles of sea ice than the average from 1979 to present. (NASA's snow ice data center)

and
Winter of 2008 had the highest N Hemisphere snow cover since records began in 1966. And it is on track for another record. Rutgers Univ

So temperatures are back to average, sea ice is well above average at the S pole, and the N. hemisphere had record snow cover. These metrics, from the scientific community, are not anecdotal but rather broad and telling descriptions of today’s condition.

I do not understand why the proponents of catastrophic man made global warming will not offer a recommended course of action to mitigate any potential warming. It just doesn't make any sense to me. And I will admit that when things don't make any sense I am less than receptive.

FYI, those of you who argue that catastrophic man made global warming is real, you would be better served by putting forward your proposals to mitigate any potential warming. Without doing that, I personally find it very difficult to take any of you seriously. Without specifying what policies you advocate, you will NOT get my support. Do you honestly expect that I will quiver in fear and grant you a blank check to use as you see necessary to battle this horrible, globe encompassing emergency.

THIS IS VERY IMPORTANT: While you can nit-pick the predictions of climate models, one of the features that is the most reliable is their prediction of future high temperatures. It should come as no surprise that the first catastrophic effects of global warming will be record high temperatures in the summer. Normally, heat events occur occasionally, but because of the build up of heat, record heat events will predictably happen more frequently and be more severe. Furthermore, the effect of such heat events are somewhat predictable because we can observe what happens when they occur occasionally.

"Few seem to realise that the present IPCC models predict almost unanimously that by 2040 the average summer in Europe will be as hot as the summer of 2003 when over 30,000 died from heat. By then we may cool ourselves with air conditioning and learn to live in a climate no worse than that of Baghdad now. But without extensive irrigation the plants will die and both farming and natural ecosystems will be replaced by scrub and desert. What will there be to eat? The same dire changes will affect the rest of the world and I can envisage Americans migrating into Canada and the Chinese into Siberia but there may be little food for any of them." --Dr James Lovelock's lecture to the Royal Society, 29 Oct. '07

In other words, non-irrigated crops (that provide a vast majority of the world's food) are our Achilles heel:

"Food riots terrify the elites much more than energy riots. Marie Antoinette was beheaded because bread, not wood or coal, was so scarce for the poor. The Roman Emperors provided free bread to a third of the population of Rome, not free wood, because they were very fearful of the hungry and jobless mob. For an increasing number of third world nations civil unrest, including violence, as a result of food deprivation is now the most significant threat to regime continuity." --Vinod K. Dar, Right Side News, 18 June 2008

Doubt climate models, but you would have to be a complete fool to throw the baby out with the bathwater and ignore what their most reliable prediction.

"We underestimated the risks ... we underestimated the damage associated with temperature increases ... and we underestimated the probabilities of temperature increases." -- Sir Nicholas Stern, author of "The Stern Report," April 17, 2008

'Many good scientists say that by 2050, almost every summer in Europe will be as hot as it was in 2003.' --'The illness in Planet Earth,' BBC, 6 July 2006

"The alternative (to geoengineering) is the acceptance of a massive natural cull of humanity and a return to an Earth that freely regulates itself but in the hot state." --Dr James Lovelock, August 2008

I am amazed with the number of people who will argue that catastrophic man made global warming is real, while simultaneously refusing to put forward any recommended policy actions of their own. They don't want to be held accountable to any specific recommendation. That would be inconvenient.

Please, I beg you, prove me wrong and make a recommendation as to what you recommend to mitigate any potential global warming.

At the recent conference on global warming in Poznan, Poland, some 650 scientists from around the globe challenged the man-made global warming claims. The dissenting scientists are more than 12 times the number of United Nations scientists (52) who authored the media hyped Intergovernmental Panel on Climate Change (IPCC) 2007 Summary for Policymakers. http://current.com/items/89613636/650_scientists_deny_man_made_global_warming.htm

Additionally, more than 31,000 American scientists have signed onto a petition that states, “There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth’s atmosphere and disruption of the Earth’s climate…” http://www.pr-inside.com/the-petition-contains-the-signatures-of-r613239.htm

Preparing to use the global warming hoax, President-elect Barack Obama has already telegraphed his intended agenda of "cap and trade" along with other heavy investments from increased taxes on the US population. Thus, Obama will increase his power and his control at the expense of the economy and the people.

If not stopped, the global warming scam will enrich the scammers (Gore and Obama’s friends), increase the power of the UN and communists like Obama, and multiply poverty and servitude for the rest of us.

Steve - I found this analysis to be interesting, but somewhat misleading. It may convey the message that the scientific basis for man made climate change rests almost entirely on the output of computer models. As you well know, that is not the case, since there is a physical science foundation that underlies what goes into the models in the first place.

Scientists from various disciplines, with different data sets and perspectives, have published studies showing the human role in climate change. These range from paleoclimatologists to biologists and entomologists.

The models are used to shed further light on the changing climate and to predict future outcomes. They're extremely important, considering that we don't have an extra 'control planet' lying around, whose atmosphere we could tinker with while avoiding harmful consequences.

However, models are not the only evidence backing up scientists' conclusions that emissions of greenhouse gases from human activities are very likely causing global average temperatures to increase.

If any readers are interested in tracing the history of climate science back more than a century, Spencer Weart's The Discovery of Global Warming is a great resource both online and in print.

AntonioSosa, you're quoting from the Senate page of a man who is unhinged from reality, Sen. Inhofe (R-Exxon). Most of those 650 "scientists" are no better than propped up corpses in terms of their respect in the community.

Pretend that we sign and ratify Kyoto. What then? How do we meet our committment to reduce our CO2 emissions? What are your suggested policies for reducing our CO2 emissions? That is what I was asking.

I thought it would have been clear when I said I suggested we replace coal fired power plants with nuclear power plants, but I see that I was wrong. I will rephrase the question from now on.

So what are your suggested policies/methods for reducing our CO2 output, BoringOrange?

CapitalClimate, you referred to a sitting United States Senator as "the noise machine". That isn't very professional and it is very disrespectful. And name calling is expressly prohibited at this site. You of all people should know that.

Thank you for the link to sciencedaily.com Dr. Tracton. While reading the article that you linked to, I noticed this link under the "Related Stories" column. My natural curiousity being what it is, I had to check it out.

I have to tell you, that article was absolutely priceless. I have placed it at the top of my "examples of agenda driven science" list.

Let's analyse and enjoy this article -

"ScienceDaily (May 30, 2008) — Yale University scientists reported that they may have resolved a controversial glitch in models of global warming: A key part of the atmosphere didn't seem to be warming as expected."

Yes, I am aware of this little "glitch" in the model. It predicts a warming trend in the upper atmosphere that has yet to materialize.

"Computer models and basic principles predict atmospheric temperatures should rise slightly faster than, not lag, increases in surface temperatures. Also, the models predict the fastest warming should occur at the Tropics at an altitude between eight and 12 kilometers. However, temperature readings taken from weather balloons and satellites have, according to most analysts, shown little if any warming there compared to the surface."

Yes, there is an embarrassing absence of the model predicted increased warming in the upper atmosphere. Got it.

"By measuring changes in winds, rather than relying upon problematic temperature measurements, Robert J. Allen and Steven C. Sherwood of the Department of Geology and Geophysics at Yale estimated the atmospheric temperatures near 10 km in the Tropics rose about 0.65 degrees Celsius per decade since 1970—probably the fastest warming rate anywhere in Earth's atmosphere. The temperature increase is in line with predictions of global warming models."

Oh, I see. If they just throw out those pesky thermometers as a means of temperature measurement, then they can create a method to measure temperature (which doesn't use a thermometer) that supports their theory. To heck with those pesky thermometers! Unless of course NASA or NOAA is busy recording record high temperatures. Oh, and if they should by chance record a record low, throw that out too.

Apparently those thermometers are only reliable when they are recording record highs. Who knew?

Andrew says”I found this analysis to be interesting, but somewhat misleading. It may convey the message that the scientific basis for man made climate change rests almost entirely on the output of computer models.”

But it does. The computer models calculate future average global temperatures. Based on these calculations, impacts are quantified; and finally, mitigating measures defined.

The problem is that the computer models are flawed and hence future temperatures, impacts on the global environment, and mitigating methods are all predicated on faulty computer output.

The IPCC models all correctly model the greenhouse gas effect whereby any increase in the earth’s surface temperature must be accompanied by a corresponding increase in the temperature in the troposphere of two to three times that on the earth’s surface. Satellite temperature data however, show that the temperature change in the troposphere is nearly the same as on the earth’s surface which indicates the IPCC models are off by 200 to 300 percent.

The reason. The IPCC models do not know how to take into account an important negative feedback mechanism that is almost completely cancelling out the greenhouse gas effect and the positive feedbacks that the models include.